Radiation shield for a cathode ray tube

Abstract

A radiation shield 14 for a cathode ray tube 10 neck 16 includes a sleeve 24 of insulating material. Bonded to the inner surface 26 of the sleeve 24 are a plurality of elongated, coaxially oriented spaced conductive elements 30. Similarly, a plurality of elongated, coaxially oriented spaced conductive elements 32 are bonded to the outer surface 28 of the sleeve 24. The inner elements 30 are offset from the outer elements 32. A conductive ring 40 is connected to each of the inner 30 and outer 32 elements along one end of the sleeve 24 and to ground potential by a drain strap 44.

What is claimed is: 
     
       1. An electromagnetic radiation shield (14) adapted for use with a cathode ray tube (10) having a neck (16) wherein means are housed for producing a modulated electron beam deflected within the cathode ray tube (10) by a yoke coil (12) which generates a magnetic field, the radiation shield comprising: a sleeve (24) of insulating material having inner and outer surfaces and an inner diameter greater than the outer diameter of the neck (16) of the cathode ray tube (10) thus allowing the sleeve (24) to be positioned on the neck (16) of the tube (10),   a plurality of first, spaced apart, parallel, conductive, elongated strips of material (30, 32) extending along the inner surface of the sleeve (24) and bonded to the inner surface (26, 28) thereof,   a plurality of spaced apart, parallel, second, conductive, elongated strips of material (32) extending along a surface of the sleeve (24) and bonded to the outer surface (28) thereof, said first conductive strips (30) being offset from said second conductive strips (32), and   means (40, 42) for electrically connecting one end each of said first and second conductive strips (30, 32) to a ground potential, whereby electromagnetic radiation from the cathode ray tube (10) is highly attenuated and the magnetic field generated by the yoke (12) is allowed to pass through the shield (14) with relatively low attenuation.   
     
     
       2. The radiation shield of claim 1 wherein said first and second elongated conductive strips (30, 32) are oriented with their axes parallel to each other and to the axis of said sleeve (24). 
     
     
       3. The radiation shield of claim 2 wherein said first and second elongated conductive strips (30, 32) are of a non-magnetic material. 
     
     
       4. The radiation shield of claim 3 wherein said connecting means comprises a ring (40) defining a slit (42), said slit (42) having substantially the same diameter as the sleeve (24) and the width of said slit (42) being slightly greater than the total thickness of the sleeve (24) so that one end of the sleeve (24) may be freely positioned into said slit (42) and means for completing an electrical connection between one end of each of said first and second conductive elements (30, 32) and said ring (40). 
     
     
       5. The radiation shield (14) of claim 4 which further comprises a conductive drain strap (44) positioned within said slit (42) and extending therefrom and wherein said slit (42) defined by said ring (40) is compressed so as to securely grasp said first and second conductive elements (30, 32) and said conductive drain strap (44) thereby completing an electrical connection therebetween. 
     
     
       6. The radiation shield (14) of claim 5 wherein said conductive elements (30, 32) are soldered to said conductive ring (40) and wherein said ring is constructed of a non-magnetic material. 
     
     
       7. The radiation shield of claim 3 wherein said first and second conductive elements (30a, 32a) extend slightly beyond the end of said sleeve (14a) and said electrical connection means is in the form of a conductive ring (50) soldered to each of said first and second conductive elements (30a, 32a) along their extension from said sleeve (14a). 
     
     
       8. The radiation shield of claim 7 which further includes a conductive drain strap (44a) fastened to said ring (50) providing a convenient means for placing said ring (50) at ground potential. 
     
     
       9. The radiation shield of claims 5 or 8 wherein said conductive elements (30, 32a, 32, 32a) are approximately one-eighth inch in width.